Bayern Munich and Germany striker Thomas Müller understands that "many find it hard to get me as a player". Photograph: Frank Bauer for the Observer

It’s turning into a beautiful September day in the Bavarian capital. Entire primary school classes and grumpy teachers who would rather be visiting a museum – “You don’t even know the players, do you?” one of them admonishes a little boy – have descended on leafy Säbener Strasse. A few thousand people regularly turn up to the open training sessions at Bayern Munich’s headquarters, just south of the city centre, but the excitement has reached new levels over the past few months. In addition to housing Germany’s most successful, most hated and best-loved football team, Säbener Strasse has become a pilgrimage site for those who do not want the summer to end. They come to see world champions. Lots of them. Any of them.

The kids hover outside the club’s glass-clad row of offices, determined to scream at all men in official Bayern training gear between the ages of 17 and 35. That is quite a big number of groundsmen, youth coaches and Bayern athletes who do not even play football, but who practise other sports such as handball or volleyball. Even from inside the complex you can hear the cheers.

However, the mood is a curious mix of quiet, feverish debates on the pitch, and post-work relaxation off it. Pep Guardiola has stayed behind on the first-team practice ground a good hour after training, and is locked in deep debate with two assistants. A few metres from them, members of the squad start trickling out of the players’ building to the faint sound of R&B, squinting their eyes at the sun. They all look as if they’re wondering whether it might be worth thinking about the plans for the rest of the day or not, then slowly wander off.

And there he is. Thomas Müller shuffles over with a wide smile and a warm “Servus.” In five seasons as a first-team footballer, he has won two doubles and a treble with Bayern, and one World Cup with Germany. He still doesn’t move, talk or look like a top international footballer, and he still couldn’t care less about that observation. That’s his secret. All that success has done is make him even more comfortable in his good-natured Naturbursche (nature boy) skin.

This is the Bavarian idea of “cool”. People in the south of Germany like it, those in other regions sometimes less so. Müller, though, was almost universally popular before he helped Joachim Löw’s team to their Rio de Janeiro triumph with five goals in seven games. Now that the 25-year-old striker from the tiny city of Pähl – on the shores of Lake Ammersee, 30 miles south-west of Munich – has returned from the Maracanã with the trophy in tow, he is destined to join other deliberately unassuming greats such as Rudi Völler and Uwe Seeler in the pantheon of national football’s heroes.

His “unorthodox playing style” – according to Löw – is a big part of the attraction, even if opposition supporters routinely fail to see what all the fuss is about. You wonder if Müller has made appearing less skilled part of his act, with his low shin pads and unkempt T-shirt that peers out over his shorts. His exploits have created their own verb. Müllern, to Müller, aptly describes his clever, unashamedly inelegant art of stabbing the ball home from unlikely angles with unlikely parts of his head or legs. “I understand that many find it hard to get me as a player,” he says. “They say: ‘Impossible, how did he do that?’ But, at some point, they maybe start thinking: ‘Oh, he’s quite good after all.’”

Müller is constantly “in a grey area”, he admits a little later – the world’s best footballer at looking fairly ordinary. “But the coaches know, so it’s never a problem for me.” Football was “like nature”, he says. “You have to adapt and find your niche, in terms of the type of player you can become, both on and off the pitch. I always knew I’d have no chance against a 1.90m, 90kg defender in a duel, so the key is to avoid these situations altogether. You have to pick your space and time.”

The first Bayern manager to really appreciate his unique talents was Louis van Gaal. “Müller always plays,” the Dutchman used to say during his two years at the Allianz Arena (2009‑11). When the 63-year-old took over at Manchester United, rumours surfaced that they would soon be reunited. How close did Müller come to heeding the call? “I know there was interest, but Man Utd were interested in a lot of players this summer,” he says, smiling. “It never really got anywhere because I had just renewed my contract [until 2019], and Bayern were clear that they saw my future here. The decision for me was an easy one.”

Müller describes the Premier League as an “obvious destination” if he was to go abroad at some stage, but he doesn’t follow it regularly. He hardly watches any football. “I used to – even Bundesliga 2 matches – but, when I’m at home, I don’t want to live in the world of football; I need to think about other things.”

The genetic makeup of dressage horses is one of those things. Müller breeds horses with his wife, Lisa, a keen equestrian who can be found driving 15-tonne trucks to tournaments at weekends. He also owns a couple of “decent” racehorses. “It’s fun to think which stallion would fit with a particular filly,” he says, and adds that he is happiest on a farm, away from the attention that playing for Bayern and Germany entails. “You meet people who come up and congratulate you [for winning in Brazil] all the time,” he says, with an embarrassed shrug. “It’s nice that we were able to make a few of them happy over the summer.” Make that 80 million.

Four weeks into the new Bundesliga campaign, Brazil is still the main talking point. Bayern, with their six world champions, have struggled to find form because of injuries – Bastian Schweinsteiger’s bruised legs need more rest – and a lack of a proper pre-season, but Müller is wary of drawing obvious conclusions. “Everyone wants to link everything to the World Cup in the early weeks of the season,” he says. “You play badly: you’ve fallen into a hole because of the World Cup. You play well: it’s the World Cup feelgood factor.

“Physically, it shouldn’t be a problem at all, especially for us younger guys. Maybe in October, November, it’ll become difficult, mentally. But you can’t think that way when you play at Bayern. You mustn’t.”

Finding motivation for the more mundane challenges of a regular campaign, after the heights of Rio, is not a problem either, he insists. “I’d be in the wrong job if I had to stand in front of the mirror and push myself to go to work every day.”

But the idea that Müller, with his spindly legs and seemingly inexhaustible stamina, enjoys nothing more than long, early runs through the Bavarian countryside, freshly baked pretzels and a bucket of milk under his arm, is disappointingly wide of the mark. “I hate running,” he says. “Forty minutes through the woods, that doesn’t appeal to me at all. It’s difficult tracking back when you’re 4-0 up as well. But, if the score’s 1-0, in an important game, then every single step is not a problem.”

Bayern have so much quality in the squad that they can pick up points in the league almost irrespective of form, but Wednesday’s Champions League game – at home to Manchester City – will act as the first benchmark for the season ahead. The 4-0 defeat by Real Madrid in the second leg of last season’s semi-final has been forgotten, Müller insists. “The result looks very bad, but these things can happen.”

Bayern probably need a bit more time to bed in new players such as Mehdi Benatia (Roma), Robert Lewandowski (Borussia Dortmund) and Xabi Alonso (Real Madrid); more time to truly gel and reach the exalted levels of their 3-1 win at the Etihad last season, the high-point of Guardiola’s first season in charge. But they will try again. “Our history and our squad demands that we challenge for every title possible,” Müller says, matter-of-factly.

Asked to predict the season ahead, he thinks for a second, and then comes up with a classic Müller line. “At Bayern, the journey is always headed for titles. So far, the travel agency haven’t called to say there’ll be complications. No rebooking, just yet.”